Conveyors

ABSTRACT

A conveyor includes a first elongated support which is movably coupled to a support structure, and a second elongated support which is supported by the first support. A conveyor belt, engaged with the first support, the second support, and a motor, tends to extend or retract the second support with respect to the first support depending on the sense of rotation imparted to the belt by the motor. However, brake means connected between the first and second supports continuously create a frictional force which prevents relative motion between the first and second supports due to the action of the free running belt. The second support includes means for directly trapping the moving belt, thereby causing the belt to apply a force between the first and second supports which overcomes the frictional force provided by the brake means and creates relative motion between the first and second supports.

United States Patent [191 Greasley [111 3,826,353 [451 Jul 30, 1974CONVEYORS [76] Inventor: Cecil Henry Greasley, 5 18 Chester Rd.,Woodford, England 22 Filed: Aug. 4, 1972 211 Appl. No.: 278,166

Primary Examiner-Richard A. Schacher Assistant Examiner-James W. MillerAttorney, Agent, or F irmAlan H. LevinejBreitenfeld & Levine [5 7]ABSTRACT A conveyor includes a first elongated support which is movablycoupled to a support structure, and a second elongated support which issupported by the first support. A conveyor belt, engaged with the firstsupport, the second support, and a motor, tends to extend or retract thesecond support with respect to the first support depending on the senseof rotation imparted to the belt by the motor. However, brake meansconnected between the first and second supports continuously create africtional force which prevents relative motion between the first andsecond supports due to the action of the free running belt. The secondsupport includes means for directly trapping the moving belt, therebycausing the belt to apply a force between the first and second supportswhich overcomes the frictional-force provided by the brake means andc-reates relative motion between the first and second supports.

7 Claims, 7 Drawing Figures l CONVEYORS This invention relates toconveyors.

According to the invention a conveyor comprises a support structure, afirst elongated support, a second elongated support, an endless conveyorbelt movable on rollers carried by the first and second supports, meansfor driving the belt in either of two opposed senses, said belt beingdisposed so that when driven in one or other sense the belt urges saidsecond support towards an extended or retracted position respectively inrelation to the first support whilst movement of the second support isprevented by brake means, and means operable to permit the secondsupport to extend or retract in relation to the first support.

The operable means mayv comprise means for increasing the energytransferred from the belt to the second support to overcome the brakemeans.

The support structure may comprise a frame or chassis to which ispivoted a further elongated support to which is pivoted the firstelongated support.

The first elongated support may be pivoted to the support structure.

The invention may be performed in various ways and two specificembodiments will now be described by way of example with reference tothe accompanying drawings, in which:

FIG. 1 is a side elevation of a first extensible conveyor; Y

FIG. 2 is part of FIG. 1 on an enlarged scale;

FIG. 3 is a side view of a control mechanism in a first position;

FIG. 4 is a side view of the controlmechanism in a neutral or datumposition;

FIG. 5 is a side view of the control mechanism in a third position;

FIG. 6 is a section on the line 6-6 of FIG. 2 with part omitted; and

FIG. 7 is a diagrammatic view similar to FIG. 1 of an.- other conveyor.

Referring to FIGS. 1 to 6, the conveyor comprises a supporting platformor chassis 10 generally rectangular in plan constructed for example ofangle girders with transverse braces. The chassis 10 is supported onspaced pairs of castor wheels ll for movement over a support surface 9such as the floor of a warehouse or loading bay.

Two brackets 12 extend upwardly at the corners at one end of the chassisand one end of a rigid beam assembly l3 is'pivoted to the brackets formovement about a horizontal axis under the control of a hydraulic ram14. The ram 14 comprises a cylinder 15, pivoted at one end to atransverse member (not shown) at the mid-point thereof, and a piston 16pivoted at 17 centrally between two laterally spaced longitudinal beams18 (only one shown) of the assembly 13, the beams 18 being connected byrigid transverse members.

A further rigid boom or beam assembly 19 comprises two laterally spacedbeams 20 with connecting transverse members and is pivoted at one endabout horizontal axis 21 to the forward end of assembly 13.

A hydraulic ram 24 pivoted to assemblies 13 and 19 is provided to pivotassembly 19 about axis 21.

Another rigid boom or beam assembly 22 comprising two laterally spacedlongitudinal beams 23 with connecting transverse members is disposedbeneath boom 19 for forward and rearward, or extension or retrac- 2tion, movement relative thereto as indicated by the arrows and describedlater.

The beam assemblies support a number of longitudinally spaced lateralrollers 25 (some omitted for clarity) for supporting the upper and lowerruns of an endless conveyor belt 26 of suitable material such asreinforced rubber. The rollers have shafts 27 mounted in bearings 28 foreasy running.

The belt 26 is driven by an electric motor 30 under the control offorward, stop and reverse switch buttons provided in control assembly 31mounted on one side of the forward end of extensible boom 22 and controlassembly 31A mounted on structure 13 near the other end of the machine.The belt 26 passes over roller 32 at the rear end of assembly 19, theroller 32 being so located in relation to pivot axis 21 that as assembly19 moves up and down in relation to assembly 13 the tension in the beltremains substantially unaltered. The belt 26 passes over roller 33 nearthe forward end of assembly 19 and over roller 34 at the rear end ofboom 22 and over roller 35 at the forward end .of boom 22.

' Hydraulic pump 36 may be manually operated by handle 37 to raise andlower the assembly l3 through ram 14 and hydraulic pump 38 may bemanually operated by handle 39 to pivot assembly 19 through ram 24. In amodification the pumps are operated electrically under the control ofsuitable switches. Also it is possible to use a single pump with achangeover valve operable to direct the fluid to the appropriate ram asdesired. Vertically adjustable castor wheels 40 are carried by theforward end of assembly 19 to support the assembly if desired on asurface such as the body of a lorry, or the floor of a container intowhich boom 22 extends.

When the belt is running in a forward direction, the tension in the belturges the boom 22 towards the extended condition, but movement of theboom 22 is prevented by brake assembly 41. When the belt is running inthe reverse direction, the tension in the belt urges the boom 22 towardsthe retracted position. Brake assembly 41 comprises a vertical-plate 42,supported from the assembly 19 and extending longitudinally beneath theassembly, and brake pads 43, 44 engageable with opposite faces of. plate42. The pads are carried by boom 22, and pad 44 is urged towards plate42 by spring 45. The pad 43 is adjustable laterally by bolts 46, andpart-threaded bolt 47 extends through'boss 47A and is engaged by nut 47Benabling adjustment of the length of spring and thus of the force withwhich pad 44 engages plate 42. a

At the forward end of boom 22 is boom extension and retraction controlmechanism 50. In the neutral position (FIG. 4) belt 26 is spaced from arod 57 fixed in the boom 22 and from-a manually operable handle 52having a cross-member 53. The position of roller 35 may be adjustedforwards or rearwards by adjustment of support bracket 54 on threadedrod 55 and is held in position by nuts 56.

' When it is desired to extend boom 22, the handle is pivoted forwardlyas in FIG. 3 to trap the belt 26 between the cross-member 53 and bar 57thus arresting movement of the belt. The tension in the belt thenovercomes the action of the brake and causes the boom 22 to extend withbelt running forward" and when the desired extension has been reachedthe handle is returned to the neutral position.

When it is desired to retract the boom 22, the handle is pivotedrearwardly with belt running in reverse as in FIG. 5 and is returned tothe neutral position when the desired retraction has been achieved.

This provides easy and smooth extension and retraction under the controlof the operator, and may be carried out at all positions of assemblies13 and 19. The boom 22 moves on peg 22A and roller 22B carried by boom19. The control buttons for the belt motor may be located at otherpositions, for example near the forward end of assembly 19. Also onlyone, or more than two, sets of control buttons could be provided.

The chassis is provided with balance weight 60 and may have means forlocking the chassis to the floor 9, such as feet 6l'carried on threadedrods extending throughthreaded brackets on the chassis.

The machine may include a power operated crab, as shown, including powerdriven wheels 70, mounted on a framework 71 supporting an electric motorand worm reduction gear for driving wheels 70.

The framework'7l is pivotted to the chassis 10 by horizontal pivot 72.When the power crab is in operation handle. 73 is screwed down forwardsso that the wheels 70 come into contact with the floor 9 and raisecastors ll clear of the floor. The loader or conveyor can then bepropelled forwards and rearwards' along the floor by a fail safepushfbutton control associated with the crab motor.

Whenever it is required to move the apparatus manually, handle 73 isoperated so that wheels 70 pivot the frame 71 upwards about pivot 72 andthus raise the driving wheels 70 clear of the floor. The chassis thenreverts to support on castors 11.

The boom 22 may extend below the level of the chassis, or assemblies l3,19, 22 may be in line. Other positions of adjustment are of coursepossible.

In a modified arrangement shown in FIG. 7, there are two separateendless belts 26 and 26A each with separate drive motors and theassemblies 13 and 19 are not pivoted together but to a support 76.

It will be appreciated that the assembly 19 could be omitted and theboom 22 secured beneath the assembly 13, or vice versa.

The chassis could be fixed to the supporting surface instead of being onwheels.

Also, the structure 13 need not be pivoted to the chassis but couldsimply extend therefrom, and in this case the ram 14 and associatedparts would be omitted.

The apparatus may be provided with mechanism by which it may be, towed;for example the chassis may be provided with a towbar attached to anAckerman steering device which can swing about a vertical axis.

In a modified arrangement, instead of trapping the belt so as toovercome the brake, the brake is released somewhat to allow extension orretraction of the boom 22 and then re-engaged to arrest the boom in thedesired position. In this case, it may be necessary to operate the brakewith power assistance, for example by way of an electric orelectromagnetic device.

I claim:

1. A conveyor, comprising: a support structure; a first elongatedsupport coupled to the support structure; a second elongated supportmovably coupled to the first support; an endless conveyor belt movableon rollers carried by the first and second supports, means for drivingthe belt in either of two opposed senses, said belt being disposed sothat when driven in one or other sense the belt urgessaid second supporttowards an extended or retracted position, respectively, in relation tothe first support; brake means for providing a continuous frictionalengagement between the first and second support to resist movement ofthe second support with respect to the first support by means of thefree running belt;.and means for directly trapping the belt to overcomethe friction force of said brake means, thereby causing the belt,depending on its sense of movement, to extend or retract the secondsupport with respect to the first support, said belt-trapping meanscomprising a handle operable to trap the belt between the handle and amember fixed in relation to the second support.

5. A conveyor as claimed in claim 1, in which the support structureincludes a main support and a further elongated support pivoted to themain support and to the first support and carrying rollers engageablewith the belt, and means for effecting pivotal movement of the furtherelongated support.

6. A conveyor as claimed in claim 5, in which the belt drive means ismounted on the further elongated support.

7. A conveyor as claimed in claim 1, in which the support structure ismounted on wheels.

1. A conveyor, comprising: a support structure; a first elongatedsupport coupled to the support structure; a second elongated supportmovably coupled to the first support; an endless conveyor belt movableon rollers carried by the first and second supports; means for drivingthe belt in either of two opposed senses, said belt being disposed sothat when driven in one or other sense the belt urges said secondsupport towards an extended or retracted position, respectively, inrelation to the first support; brake means for providing a continuousfrictional engagement between the first and second support to resistmovement of the second support with respect to the first support bymeans of the free running belt; and means for directly trapping the beltto overcome the friction force of said brake means, thereby causing thebelt, depending on its sense of movement, to extend or retract thesecond support with respect to the first support, said belt-trappingmeans comprising a handle operable to trap the belt between the handleand a member fixed in relation to the second support.
 2. A conveyor asclaimed in cLaim 1, in which the belt trapping means is mounted at aforward location on the second support.
 3. A conveyor as claimed inclaim 1, in which the brake means comprises brake pads carried by thesecond support engaged with an elongated brake plate carried by thefirst support.
 4. A conveyor as claimed in claim 1, including hydraulicmeans for pivoting the first support in relation to the supportstructure.
 5. A conveyor as claimed in claim 1, in which the supportstructure includes a main support and a further elongated supportpivoted to the main support and to the first support and carryingrollers engageable with the belt, and means for effecting pivotalmovement of the further elongated support.
 6. A conveyor as claimed inclaim 5, in which the belt drive means is mounted on the furtherelongated support.
 7. A conveyor as claimed in claim 1, in which thesupport structure is mounted on wheels.